In the internal combustion engine by-products from the combustion chamber often blow by the piston and admix with the lubricating oil. Many of these by-products form acidic bodies within the lubricating oil leading to the formation of sludge and corrosive bodies detrimental to the engine bearings and parts. Typical acidic bodies produced include sulfur acids, produced from the oxidation of sulfur-containing compounds in the fuel, hydrohalic acids, derived from halogen lead scavengers in the fuel, and nitrogen acids, produced from the oxidation of atmospheric nitrogen within the combustion chamber.
It has been found that these acidic bodies cause degradation of the lubricating oil to form sludges which settle out on parts of the engine. The acid bodies also are corrosive to the metal bearings and parts of the engine causing rapid wear and early breakdown of the engine.
Overbased calcium and barium sulfurized phenates have been employed to neutralize the acid bodies and to disperse sludge within the lubricating oil. Although the overbased barium and calcium phenates neutralize the acid bodies and are quite effective detergents; they do not possess the desired degree of rust inhibition needed for a more complete protection of the engine parts. Magnesium phenates have been developed which do impart a higher degree of rust inhibition to the lubricating oil. These magnesium phenates, however, are more expensive and are considerably more difficult to prepare.
It is, therefore, an object of this invention to provide an improved method for preparing overbased magnesium phenates.
It is an additional object of this invention to provide a method for preparing overbased magnesium sulfurized alkylphenates.
It is another object of this invention to provide a method for preparing overbased magnesium sulfurized alkylphenates from process steps which do not employ sulfurized alkylphenol as a starting material.
Other and further objects of this invention will become apparent upon the following description of the invention.